Weighing the Water Solution, Will a New Ground Water Replenishment System Drought Proof California?


picture: JNovak

Visitors to Disneyland likely don't know that when they sip from Disney water fountains that the great tasting aqua treat was once streaming through a public sewer. Not to worry though. That sewer water is actually substantially cleaner and more carefully filtered than the water consumed in the average American household. Moreover, the new system providing Disney's water could be the most viable means of drought proofing a state that faces some potentially serious water issues in the coming years.Orange County Water District officials are currently testing the Groundwater Replenishment System, which recycles water using microfiltration, reverse osmosis, ultraviolet light, and hydrogen peroxide disinfection. The system, the largest of its kind and pet-named toilet-to-tap, can purify around 70 million gallons (265 million liters) of sewer water a day and provide clean drinking water for over 500,000 Californians.

Could California's Groundwater Replenishment System Make the State Drought Proof?
Maybe. The system seems to be one of the more practical options for addressing California's water issues. Our water supply has been traditionally undervalued because the government subsidizes the importation programs that bring much needed water to America's more arid areas. These programs are generally designed to provide water for agricultural purposes. The low cost of water has left little incentive for private parties to research and develop new technologies for providing water to our communities. The relative economic benefits of such research were just too low to permit it. That, however, is changing.

"Within three years, the price of imported water will be $800 per acre foot, and projects like this, even without outside funding, will become viable," said said Michael Markus, general manager of the Orange County Water District and the chief engineer behind its Groundwater Replenishment System. An acre foot of water is about a year's supply for two families.

The Groundwater Replenishment System, on the other hand, can produce water for about $600 an acre foot, not including subsidies it received for the initial capital investment. Along with aggressive water conservation, the system could be self-sustaining. The system is innovative in that it pumps water back into the aquifer. The water is pumped underground, which helps to form a barrier against seawater intrusion on groundwater sources. The remaining water is filtered back into the aquifers that can supply water to around 2.3 million Californians.

Desalination, another method being explored, presents certain marine eco-system risks, such as sucking marine life into the intake pumps. The cost of removing such a large amount of salt from the water is also relatively high, and there are almost 30 times more dissolved impurities in desalinized water than in water provided by the Groundwater Replenishment System.

California is already using gray water recycling. Gray water recycling includes any water that has been used in the home, except water from toilets. Gray water which includes dish, shower, sink, and laundry water comprise 50 to 80 percent of residential "waste" water. This may be reused for other purposes, including landscape irrigation. Jaymi recently wrote about gray water recycling in San Jose.

The Groundwater Replenishment System produces drinking water that far exceeds the U.S. regulations for cleanliness and replenishes our groundwater at the same time. And the program has already been implemented in other countries. For example, according to an NY Times article, several smaller plants in the southern African country of Namibia add the purified wastewater directly into the public drinking supply without first percolating it through an aquifer or settling it in a reservoir. In the industry, it's called "direct potable reuse."

More on Water Recycling:
Grey Water Guerrillas
Quench Water-Recycling Shower - Guilt-Free Indulgence?
Cool but Ugly: Argentinean Water Recycling Toilets

Tags: California | Water Conservation